Tuning dial



Nov.. 9 .1926. HOSZQ R. WILLIAMS TUNING DIAL Filed Jan. 26, 1926 20 l v /f/,z ill, 66

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, INVENTOR. fw. 5, Jef/ys wu. L/HMS Passed Nav. 9', 192e.

UNITED s'rA'iEs PATENT orrica.

anys WILLIAMS, or OAKLAND, CALIFORNIA.'

TUNING DIAL. l

Application led January 28, 1926. Serial N0. 88,839.

This invention relates to radio receiving apparatus and particularly pertains to a tuning dial for adjusting condensers and like instruments of radio receiving sets.

It is the principal object of the present invention to generally improve devices of the character referred to by providing a tuning dial which may be very accurately adjusted to finely vary the capacity 0f a condenser or like instrument, and which is so` is exemplified in the following description and illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a central section through a tuning 'dial embodying the preferred form of my invention.

Fig. 2 is a perspective view of a dial constructed according to my invention with' parts broken away to more clearly disclose certain features of construction.

Fig. 3 is a diagrammatic view showing the manner in which the vernier adjustment of the tuning dial is obtained.

Referring more particularly to the accompanying drawings, 10 indicates a panel 'of insulating material such as .usuall employed in supporting the various instruments of a. radio receiving apparatus. Mounted on this panel 10 is a tuning device 11 which embodies the preferred form of my present invention. This device may be employed for adjustin condensers or similar instruments of a radio receiving a paratus, and is connected with the panel 10 ymeans be fastened by of a back plate 12 which may e exterior surscrews or other means to t face of the panel 10.

The shaft of the instrument operated by the tuning device is indicated by the numeral' 13 and projects through 'the panel 10 and centrally through the back plate 12 as .illustrated in Fig. 1of the drawings.' Mounted on the condenser shaft 13 is a tuning dial sleeve 14. .This sleeve is formed atyits outer end with an enlarged bore within which a split cone 15-is mounted. This cone 15 is connected with the inner end of an adjusting screw 16 which is threaded through the outer end of the sleeve. By threading this adjusting screw toward the inner end of the sleeve, the split cone 15 is contracted about the condenser shaft 13 and clamps the same to the tuning dial sleeve 14.

e inner end of the tunin dial sleeve 14 is formed with a concentric isk 17 which is disposed parallel to the back plate 12 and is closely adjacent thereto. This disk 17 carries a hollow semi-spherical ltuning dial 18.

The lar er 'endl of this tuning dial is disposeda jacent the panel and is secured to thel peripheral edge of the disk 17, as disclosed in Fig.,1. l

Arranged over the tuning dial is a loggin dial 19 which is shaped similarly to the diz 18, and which is fitted withA a fixed knob 19h. This logging dial 19 isv secured at its outer end to a logging dial sleeve 20 which is rotatably disposed on the timing dial sleeve 14. The inner end of the logging dial sleeve 20 abuts against the outer surface of the disk 17 and maintains the logging dial 19 at a spaced distance from the tuning dial 18. This mounting of the dials permits vthem to be rotated at relatively different speeds without friction between their adjacent surfaces.

Secured on the inner end of the logging dial sleeve 20 is a spur pinion 21 which meshes with an idler gear 22 rotatably disposed on a boss l23. This boss is formed integral with the back plate 12 and projects upwardly through an arcuate slot 24 formed ill) in the disk 17 and concentric to its center. This boss 23 also serves as a mounting for a light bulb 24C. the purpose of which will be hereinafter described.

The idler gear 22 is in mesh with aninternal ring gear 26 formed integral with the disk 17 and disposed adjacent its outer periphery. Therefore, rotation of the logging dial in one direction will imp art rotation to the tuning dial in the opposite direction at a very great reduction in speed. That is, the logging dial will turn a consid erable number of turns while turning the tuning dial but once. This permits a very tine adjustment of the condenser. to be obtained inasmuch as the slow moving tuning dial is connected with the condenser shaft 13.

It should be' stated that both the dials are formed of translucent material and for .this purpose the light bulb 25 is provided. This light is provided with a reflector 25? so that the rays emanating from the light Will be reflected through the dials at the reading portion thereof. The circuit of the light may be completed in any preferred manner.

' One-half of the circumference ofthe tuning dial 18 is divided into 80 divisions by radial lines 18n appropriatelyimprinted thereon. These lines are preferably formed of black opaque substance. Only one-half of the circumference of the tuning dial is divided-by these radial lines due to the f act that the range of movement of the tuning dial is limited to a one-half turn by the length of the arcuate slot formed concentrically in the disk 17.

The entire circumference of the logging dial is divided by opaque radial lines 19a into 150 divisions. As the division lines on the logging dial apart or five divisions less to its half circumference than the tuning dial, a very accurate Vernier action between the dials is providedl as will be described.

As before stated both of the tuning dials are formed of translucent material. The major portion of the surface of the inner or tuning dial 18 is preferably stained a dark color, such as red. The inner marginal edge of the dial which bears the scale for'the radial lines and a helically arranged indicating band 17 which extends halfway around the dial between its outer and inner margins are left transparent. The purpose of this transparent indicating band will be hereinafter described..

The outer edge of the dial is left transparent so that the numerals imprinted thereon may be read through the logging dial. As the helical indicating band is also transparent it can be clearly distinguished through the logging dial. This latter dial is translucent and is preferably frosted so that the helical indicating band and the radial lines may be readily distinguished are spaced slightly farther` therethrough. Due to the frosted surface of the logging dial, the stations may* be, readily logged thereon by marking with ink or other suitable substance.

For timing purposes I provide a stationary scale or indicator 27 which is calibrated into five divisions which are numbered zero to five, each division equalling five meters .of broadcasting wave band. These divisions on the scale 27 are one-fifth larger than the divisions on the tuning dial 18. Therefore, the calibrations on the indicator 27 may be used to divide the divisions on the tuning dial into-fifths or one meter as the divisions on the tuning dial likewise represent ve meters.

By the arrangement just described the timing dial can be accurately adjusted to within one meter. This is acomplished as follows: Reference being had to Fig. 3, where the indicator 27 is shown and where the radial lines of the timing dial are indicated, the radial line closest to the zero on the indicator denotes the major reading. In the event that the station being tuned in on a wave band which is not a multiple of .f ive, the tuning dial must be turned from register with the zero on the indicator 27 until the proper radial line registers with the correct calibration on the indicator 27. That is, the major reading on the tuning dial at zero plus the reading of the calibration on the scale 27 with which one radial line registers is the nal reading.

For example, if the final reading is-to be 26, the numeral 25 on the tuning dial is moved until it is closely adjacent to zero on the indicator 27, or until the next adjacent radial line registers with number one calibration on the indicator 27. As the distance between zero and number one calibration on the indicatorv is one-fifth greater than dial represents five meters, one-fifth of this 1 distance would indicate one meter. Thereiin" fore, by registering the radial line adjacent Y number 25 radial line with the number one calibration on the indicator would mean that the tuning dial was set at 26 meters. This would be determined by adding the reading of the radial line adjacent the zero calibration on the indicator 27 to the value of the calibration on the indicator 27 with which one radial line on the tuning dial is in register. 1 Inasmuch as the calibrations on the indicator 27 are spaced apart the same dist-ance as the division lines on the4 logging dial, when a station has been tuned in, a radial dial.

.mark may then be line on the logging dial will register with the radial line on the tuning dial which is in alignment with the proper calibration on the indicator scale 27. To log the station a mark is made on the exterior surface of the loggingdial at the point where the radial lines of the dials register and cross the visible helical indicating band on the tuning The call letters of the station may be also logged on the logging dial adjacent the mark.

In tuning in a station already log ed, the logging dial is turned until the mar ing of the station on the logging dial simultaneously registers with the helical indicating band. and with the radial line on the tuning 'dial which will also be in register with one of the calibrations on the indicator 27. This will'set the condenser or instrument operated by the dial to the proper wave band forl receiving from the logged station.

To tune in a station, it will be assumed for example that the station broadcasts on a 361 meter wave band. To tune in this station it is first necessary to subtract 200 meters from the 361 meters, leaving 161 meters. The knob of the logging dial 1s then turned to turn the tuning dial until its 160 division number comes adjacent the zero mark on the indicator 27. This movement is continued until the division line at the right of the 160 radial line registers with number one calibration on the indicator scale 27. This will be the correct position for receiving signals at 361 meters.

Immediately below the scale 27 where the registering radial line on the logging dial crosses the helical indicatingr band it will be in register with the radial line on the tuning dial which is in register with number one calibration on the indicator scale `27. A made on the logging' dial at the point where the radial line of the logging dial intersects with the helical indicating band. The call letters of the station may also be marked adjacent the mark.

There are inherent discrepancies and variation in capacitative values of condensers throughout their range though the straight line kind approximate closely. Therefore, scale 27 and dial 18 will only approximate to the correct reading in meters. That is, with a perfectly constructed straight line condenser, the readingrwould be correct but i any departure from that would cause a similar deviation from correct reading on scale 27 and dial 18. l

The processes of tuning can be continued and assisted by scale 27 until the station sought comes in clearest and then logged, by afiixing a mark on the logging dial (tof gether with the station call letters) over the helical band where any radial line on logging dial 18, within the limits superimposed on a radial line of the tuning of scale 27, is i dial. The numeral on 'scale 27 adjacent to the superimposed radial lines can lbe added to the call letters.

A Due to the fact that the logging dial turns a considerable number o complete revolutions to each one-half revolution of the tuning dial, it will be seen that the logging space will be extremely'long.

I have found in actual practice -that on a dial four` inches in diameter and constructed 'ml accordance with my present invention. that a logging chart equal to'one hundred inches in length is provided.

'It is therefore ymanifestthat where the stations are close together at the lower wave lengths that the radial lines are the furthest apart and a greater space is provided for logging.

The tuning dial here disclosed is of comparatively inexpensive construction and may befeasily and quickly assembled or disassembled. To disassemble the dial, it is only necessary to remove the cap 2021 which is frictionally held in the outer end of the logging dial sleeve and to turn the screw 16 until the split cone l5 releases the condenser shaft 13. The entire outer dial may then be removed, permitting access to be had to the interior thereof. Likewise, if it is desired to remove the condenser or the instrument operated by the dial for repairs it may be easily disconnected from the dial by the operation just described.

It is manifest from the .foregoing that I have provided a dial by'means of which a very accurate tuning in may be effected and which is provided with ample space for correctly and properly logging stations.

l/Vhile I have shown the preferred form of my invention, it is to be understood that various changes in its construction may be made without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, what ent is:

1. A device of the character described comprising a tuning dial adapted to be fixed to an instrument to be adjusted, a translucent logging dial arranged over the tuning dial and through which the tuning dial is visible, said common axis, an operative connection between the dials whereby rotation of the logging dial will revolve the tuning dial at al comparatively slower rate of speed, indicating means cooperating with the tuning dial to visibly indicate the position of the instrument beingoperated thereby, and cooperative logging dial and on the logging dial to indicatelogging points for recording the position of stations received by certain settings of the dials, said logging indicator means indicating dials being rotatable about a' tion of the instr points of logging in a convolute path from the outer to the inner circumference of the logging dial as the dials move through their cycle of operation.

2. A device of the character described comprising a tuning dial adapted to be xed to an instrument to the adjusted, a logging dial arranged over the tuning dial, saidy dials being rotatable about a common axis, an operative connection between the dials whereby rotation of the logging dial will revolve the tuning dial at a comparatively slower rate of speed, indicating means cooperating with the tuning dial to visibly indicate the posiunient being operated thereby, said logging dial being of translucent material, a helical logging indicator on the tuning dial visible through the logging dial and adapted to indicate logging points on said logging dial whereby certain settings of the dials may be recorded, said indicator -indicating said logging points on the logging dial in a path of progressively decreasing convolutions from the outer to the inner c1rcumference of the logging dial as the dials move through their cycle of operation.

3. A device of the character described comprising a semi-spherical tuning dial adapted to be xed on the'shaft of a condenser, an indicator, cooperative means on the 'indicator and on the tuning dial for accurately indicating the capacity of the condenser at various settings of the dial, a logging dial of a shape similar to that of the tuning dial adapted to be arranged over the tuning dial and to rotate about the same axis as the tuning whereby lit may be rotated, a geared connection between the tuning dial and the logging dial whereby rotation of the latter will revolve the tuning dial at a relatively slower rate of speed to obtain a Vernier adjustment of the same, cooperative means on the tuning dial and on the logging dial for indicating a logging cha-rt on the logging dial of helical form and extending between the outer cir-v cumference of the logging dial and the inner circumference thereof, said logging dial being transluscent vwhereby the tuning dial may be visible therethrough. y

4. A device of the character described comprising a semi-spherical tuning dial adapted to be fixed on the shaft of a condenser, an indicator, cooperative means von the indicator and on the tuning dial for ac-l curately indicating thecapacity of the condenser at various settings of the dial, a logging dial of a shape similar to that of the tuning dial adapted to be arranged over the tuning dial and to rotate about the same axis as the tuning dial, a geared connection between the tuning dial and the logging dial whereby rotation of the latter will revolve the tuning dial at a relatively slower rate of speedl to obtain a Vernier adjustment of the 'comprising a tuning dial dial, a knob on the logging dial same, cooperative means on the tuning dial and on the logging dial for indicating a loging chart on the logging dial of helical orm and extending between the outer circumference of the logging dial and the inner circumference thereof, said dials being translucent, and illuminating means interiorly of the dials for illuminatin the same.

5. A device of the c aracter described adapted to be fixed to an instrument to be adjusted, a translucent logginff dial arranged over the tuning dial, said dials being rotatable about a common axis, indicating means cooperating with the tuning dial for indicating the position of the instrument beingv operated thereby, an operative connection between the dials whereby rotation of the logging dial will revolve the tuning dial at a relatlvely slower speed, and helical indicating means on the tunino dial visible through the logging dial, an indicating means on the logging dial coop erating with the helical indicating means on the tuning dial whereby a helical logging chart willbe provided. f

6. A device of the. character described comprising a rotatable tuning dial adapted to be fixed to the shaft of an instrument to be adjusted, an indicator, cooperative means on the indicator and on the-tuning indicating the position of the instrument operated by the tuningv dial, a translucent logging dial arranged over the tuning dial and rotatable about the same axis as the tuning dial, an operative connection between the logging dial and the tuning dial whereby rotation of the former will revolve the tuning dial ata relatively slower speed, helical indicating means on the tuning dial visible through the logging dial whereby 'a helical dial for l logging chart of considerable length will be v by the tuning dial, a loggingdial of a shape similar to the tuning dial adapted to be arranged thereoverto rotate about the same axis, gear connection between the tuning dial and the logging dial whereby rotation of the lat ter will revolve the tuning dial at a relatively slower rate ofspeed, a helical indicator on the ,surface of the tuning dial and extending a distance equal to the length. of the path of movementof the tuning dial, said dials being translucent, lighting means arranged interiorly of the dials whereby said helical indicator will be visible through the loggingr dial, and means on the loggingdial adapted to cooperate with said helical indicator to provide a helical logging chart, of.

means for rotating the logging dialf f" dcator, radial lines on said tuning dial adapted to4 cooperate with the calibrations of said indicator,` a geared connection between the logging dial and the tuning dial whereby rotation of the former will rotate the tuning dial at a relatively slower rate of speed7 said logging dial being translucent whereby the readings of the tuning dial will be visible through the logging dial and may be logged thereon.

lRI-IYS l/VILLIAMS. 

